Power Steering Failure

T

Tamir

Member
 Israel
Hey everyone. I own a '04 Z4 e85 3.0i automatic transmission. I've had this problem for a while but back then the EPS warning light would disappear after one more key switch attempt. Nowadays it's gone worse, to a point where I need to leave the engine running for almost 10 minutes, then kill the engine and start it up again to have the EPS light disappear. I'd also like to add that it's not random, it happens every time.

So I began researching online and I read that I must check the battery and make sure it the voltage doesn't drop below 11v, the check showed 8v which also explained why lately the interior lights would lose power when I turn the engine on. As it turned out the old battery was bigger than the size that's supposed to fit this car it was 72Ah instead of 60Ah, I obviously changed it to a new Bocshe that sits well in its place. Unfortunately it did not fix the EPS problem.

The thing is that no one in my country knows how to handle these electrical power steering columns except for BMW service centers and we're probably talking about $3,000 cost from what I read here on the forums. So I hope new discoveries are found regarding this problem.

Thanks in advance :headbang: :headbang: :cry:
 
firebobby said:
Welcome to the forum, what country are you from ?
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firebobby said:
Another shy newbie ??
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Hey man, thanks for having me. :)
I'm from Israel. Still struggling with this problem, it's very time consuming trying to diagnose this
 
The EPS basically consists of a torque sensor, motor and an ECU (EPS module). Your fault is almost certainly one of them! Maybe this thread will be of some help to you... it shows exactly what's involved with some great images:

https://z4-forum.com/forum/viewtopic.php?f=34&t=82880
 
Before spending lots of money you could try the simple thing that cured my same problem.

While car is running, turn the steering to full lock both ways then back to centre (check that the front wheels are straight) turn off. Wait 2 mins then start the car.

Mine had the same problem as yours, my EPS stopped working altogether! Had to drive round without power steering for days before trying this simple solution. This was 2 years ago now & have not had a problem with it since.

Hope this helps.

Cheers, tug :thumbsup:
 
So I've tried so many things but this EPS problem keeps coming back the next day. One thing I noticed that makes a difference is when I reset the steering angle sensor and erase error codes (even though it says there's none) the warning light disappears for a few hours but always comes back.
Sounds like steering angle sensor? Does it mean I'm going to have to take the entire column out?
 
Tamir said:
Sounds like steering angle sensor? Does it mean I'm going to have to take the entire column out?
Click to expand...

Sounds like it, unfortunately. It's item 15) in that link I posted.
 
wasnt sure if to make my own post or comment on this one.

i have the same issue where by eps light is on, reset codes even tho there are none and it goes away but returns if you switch the car off and then back on

my problem happened over night and had been fine up to that point, i have been able to gain access the module once i had cleared the error memory but only lasted till i turnt the car off

this time even if i clear error memory in inpa it remains, going to the steering angle sensor every thing looks ok as does the eps.

i have used a code reader at a garage and it stated 611D power supply faulty . but googling that code returns nothing


since then i have not been able to access the module. but before i cleared loads of stored code there was one listed as 41 vehicle angle sensor faulty but this has not returned,
 
I'm still experiencing this problem. There's one positive thing though, the warmer it gets the better my steering gets - during warmer days like today I can start the car without EPS errors at all, no need to wait.

It's been about 3 months trying to diagnose this problem, there's nothing that can fix this as far as I'm concerned so I ordered the entire steering column on eBay, I'll replace it and update.
 
well, a strange thing happened today, the cars been sat pretty much since i posted the last post, it was a nice day so thought id take the missis to work in the z4 even tho the steering is dead, its manageable once you get going

pulled it out the drive and as im on a corner house i pulled it round to the front door went inside and came back out and the steering light had gone and i had steering back for the entire journey, so thought best time to get to my mates with the scanner,.

had the car off and back on and still no lights, so while his scanner was charging we looked at the tracking which was out a bit so sorted that,
got the car off the ramp and the light is back on

scanned the car and it brought a fault code up for the instrument cluster , went in to that and read the codes and it stated open circuit but unknown fault, the system wouldn't let me reset it with the car running but did allow me with the car off and ignition lights on



so cleared that and the light goes straight out, turn't the car off, waited 15 minutes and get the light back on straight away, scanning and clearing that open circuit fault clears the steering light


so now is this indicative of the ribbon cable? it seems an intermittent fault and doesn't sound like an actual break in a wire, is it possible something in the instrument cluster is broken??

surely if there was an actual open circuit the steering wouldn't work, but as long as the ignition isn't turn't off it works
 

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I also have the same error codes. This is so intermittent it's frustrating. Nowadays when it's a bit warmer outside, especially where I live, most of the time the car starts up with fully working power steering, sometimes with the EPS light on sometimes off, but it's just working when it's hot outside.

Though at night when it's cold, it may take up to 15 minutes of idling to get the EPS to work. (no :driving: for me)
 
To eliminate the basics firstly make sure your battery is good, low voltage can cause all sorts of lights to trigger and the eps is one of them. You want an absolute minimum of 12.4 Volts with the engine off and around 13.7v - 14.5v with the engine at idle.

Someone previously posted with similar faults and it turned out to be a break in the EPS harness plug/wiring under the column.

This is also worth a read to see what's actually going on inside the EPS column assembly and the angle sensor assembly in particular including the ribbon connector. https://z4-forum.com/forum/viewtopic.php?t=82880
 
For that I'd have to pull the entire steering column out, which is something I don't fancy doing atm
Will first see how this summer treats my EPS, maybe it will get better... I'll save up for next winter to buy a new/repaired column.
 
Tamir said:
For that I'd have to pull the entire steering column out, which is something I don't fancy doing atm
Will first see how this summer treats my EPS, maybe it will get better... I'll save up for next winter to buy a new/repaired column.
Click to expand...

I wasn't suggesting a drastic strip down quite yet! It's just a useful reference to see what the system is made up of :rofl:

I'm pretty sure you will can fix it without replacement if you methodically work through the suggestions on the forum, the problem won't be anything new. Keep us updated :thumbsup:
 
I finally managed to get a replacement steering column, only to find out that my Z4 now suffers from the infamous sticky steering problem. Has anyone experienced sticky steering right after installing a newer column?

My first guess is that the specialist who installed the new column had sealed all parts so tightly as well as the motor to the column that there's no free space for the wheels to try and go back to the "0" angle.

I must say it ruins the experience driving this car. The thing I like the most about driving my Z4 is the precise steering and how light the car feels in high speeds and in turns. This issue gives that all away. Not to mention I feel it's dangerous to drive it with the sticky steering, I find myself making small adjustments so I don't crash into the sidewalk or cars coming in front. Feels like riding a bike. :(

Will keep the post updated, and will appreciate any helpful input. :driving:
 
Try and adjust the concentric ring, the part where the motor fits to the column. It needs very slight adjustment either way to see if the steering gets better.
It helped on my sticky steering
 
firebobby said:
Try and adjust the concentric ring, the part where the motor fits to the column. It needs very slight adjustment either way to see if the steering gets better.
It helped on my sticky steering
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I tried to move it left and right but it's very tight, couldn't move it not even 1 mm :)
To your knowledge do I need to take the part out again or can it be done from under the steering wheel?
 
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